Device for throwing a switch point

ABSTRACT

A rail support forms an upwardly directed generally planar slide face, a longitudinally extending running rail secured to the support and having a foot. A longitudinally extending switch blade adjacent the rail is shiftable above the slide face between an inner position closely transversely juxtaposed with the running rail and an outer position transversely spaced from the running rail. A frame defines a longitudinal outer axis spaced transversely along the slide face from the running rail, a longitudinal middle axis between the outer axis and the running rail, and an inner axis between the middle axis and the running rail. Respective outer, middle, and inner rollers are carried on the frame and rotatable about the respective axes. The middle roller is axially offset from the inner and outer rollers and is of such a diameter that it radially overlaps the inner and outer rollers.

FIELD OF THE INVENTION

The present invention relates to a device for throwing a switch point. More particularly this invention concerns a switch where the switch blade rides on a carriage supported on rollers.

BACKGROUND OF THE INVENTION

Throwable blade devices in switches can have different geometries depending on the country. In most European countries, usually blade devices with low blade profiles, so-called shallow depth rail profile, are used. These have the advantage that an open space is provided under the blades that can accommodate a clip for a running rail and in particular, the blade foot, even after final machining, still has a significant width as a support surface on a slide frame.

In another main group of blade devices for switches, a symmetrical rail cross-section is used for the blade profile, which usually corresponds to the regular rail profile that is used for track rails as well. The height of the blades thus approximately corresponds to the height of the running rail, so-called full depth rail profile.

For example, this group includes the blade profiles manufactured in accordance with the AREMA standard. Part of the blade foot in the inner region of the blade device is significantly narrower than in the blade devices described above and than in BS (British standard) blade profiles, for example.

The sliding action of the blade profiles inside the switch usually occurs with the aid of roller devices that support the blades. The typical roller device for this purpose entails inner and outer rollers rotatable about parallel axes and transversely aligned with each other, and a slide frame or chair in which they are journaled. This slide frame is typically biased upward to support the blade above a so-called slide plane formed by or carried on the underlying sleeper. When a substantial force is exerted downward on the switch blade, the rollers and carriage plate move downward and the foot of the blade comes to rest on this slide plane. Such systems are described in DE 44 34 143 and U.S. Pat. Nos. 5,622,340, 5,628,480, 6,189,840, and 6,464,177.

In such devices the foot of the switch blade is quite narrow since it must fit with the running rail. As a result continuous and uniform rolling is either only possible to a limited degree or is not possible at all because the distance between the rollers is too great. The roller diameters cannot be reduced too much without reducing their effectiveness. The blade foot in this instance travels onto the inner roller and then tilts with the inner edge of its blade foot into the gap between the inner and outer rollers before it is lifted up again by the circumference surface of the outer roller and transported further. This bumpy rolling process can cause damage to the roller assembly, caused by the possible impact of the blade with the roller frame between the rollers, even though the blade is typically not loaded during the adjustment movement between its inner and outer positions. Furthermore, this discontinuity can significantly increase the blade throwing force and can consequently cause the switch to move sluggishly.

OBJECTS OF THE INVENTION

It is therefore an object of the present invention to provide an improved device for throwing a switch point.

Another object is the provision of such an improved device for throwing a switch point that overcomes the above-given disadvantages, in particular that in particular permits an easy, smooth movement, even of a switch blade with a narrow blade foot.

SUMMARY OF THE INVENTION

The instant invention is used in combination with a rail support forming an upwardly directed generally planar slide face, a longitudinally extending running rail secured to the support and having a foot with a predetermined transverse width, and a longitudinally extending switch blade adjacent the rail and shiftable above the slide face between an inner position closely transversely juxtaposed with the running rail and an outer position transversely spaced from the running rail. The device has according to the invention a frame defining a longitudinal outer axis spaced transversely along the slide face from the running rail, a longitudinal middle axis between the outer axis and the running rail, and an inner axis between the middle axis and the running rail. Respective outer, middle, and inner rollers are carried on the frame and rotatable about the respective axes. The middle roller is axially offset from the inner and outer rollers and is of such a diameter that it radially overlaps the inner and outer rollers.

In other words, this object is attained according to the invention by virtue of the fact that axially offset from the inner and outer rollers and approximately in the middle between them there is a middle roller so that as the blade rides on moving from the inner roller to the outer roller it rides on the middle roller. In a rolling switch-throwing process, this design permits the narrow lower face of the switch blade to always roll in a definite, preferably stable fashion on at least two rollers of the triple roller arrangement. More precisely stated, it is possible for the maximum distance between the roller axes of the middle and inner roller or between the middle and outer roller to be defined so that, when the blade foot is situated approximately in the middle between two rollers, the edges of the blade foot still rest on or contact two rollers. Thus roller diameters and axis spacing is such that the outer peripheries of adjacent rollers are spaced apart at the slide plane by a distance shorter than a transverse width of the lower face of the switch-blade foot.

In an advantageous embodiment of the invention, the roller circumferences of the rollers of the roller pair and of the laterally offset roller overlap one another. Because the roller circumferences of two successive rollers—one of which is always the laterally offset roller—overlap each other, this securely closes or bridges over the empty space between the inner and outer rollers of the roller pair. But this can also be guaranteed even if the empty space between these rollers is slightly larger than the width of the narrowest blade foot in use.

According to one embodiment of the invention, the middle, laterally offset roller is preferably embodied so that its vertical position or height can be adjusted. This makes it possible to achieve a definite presetting so that the middle roller is at least the same height as the adjacent surface of the support or better still, projects slightly above it. The height of the roller here can be adjusted by means of an eccentric adjusting mechanism or by means of an eccentric roller bearing so that the height of the roller can be easily and smoothly adapted to the height of the roller pair and/or of the slide frame and locked in the set position.

The rolling process can be further improved if the inner roller onto which the blade first rolls is set lower than the outer roller.

Primarily if the laterally offset roller is not height-adjustable, in an advantageous embodiment of the invention, the rollers are set and/or positioned so that the height of the laterally offset roller is between that of the inner and outer rollers. As all of the rollers cooperate, this results in a inwardly inclined roller plane, which slopes downward toward the running rail.

According to another embodiment of the invention, the middle roller and the parallel, adjacent roller pair are situated on a common plate of the slide frame. The ribbed plate is preferably a component of a slide frame that accommodates the rollers with their for example eccentric adjusting mechanism. The slide frame, which is integrated into the support in sliding fashion makes it possible, when adjusting the roller arrangement, to shift the outer roller as far as possible toward the blade foot so that when the blade is thrown, the rolling movement begins as early as possible.

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is a perspective view of a device for throwing railroad switch blades, having a running rail is clipped to a support, and having a switch blade, which is depicted both in a position resting against this running rail and in a position spaced from it and is supported on rollers of a roller assembly likewise accommodated in the support, which assembly is contained within a slide frame;

FIG. 2 is a side view of the switch-throwing device according to FIG. 1;

FIG. 3 is a perspective top view of a detail of the switch-throwing device, showing the roller assembly comprised of two rollers situated one behind another and in line with each other and a middle roller laterally offset from them; and

FIG. 4 shows the structure of FIG. 3 from the right, the adjusting side.

SPECIFIC DESCRIPTION

As seen in FIG. 1 a switch blade-throwing device 1 is carried on a support 9 with a running rail 2 also clipped to the support 9. The blade tip 4 of a switch blade 3 rests against the running rail 2 (see FIG. 2) in an inner position shown in solid lines and is spaced transversely from it in an outer position shown in broken lines. The blade 3 has a narrow foot 7 that supports the switch blade 5 rests and rolls during adjusting movements on a roller plane of a plate-like slide frame 8, which for positioning purposes, is situated so that it can move in linear fashion on a support 9 of the switch blade-throwing device 1.

In the illustrated embodiment, a slide frame 8, which functions as a base support element and is equipped with a ribbed plate 13, in cooperation with a top plate 10 (see FIG. 4), on the one hand provides a height-adjustable support for inner and outer rollers 11 a and 11 b that are centered on respective axes 14 a and 14 b. In addition there is a middle roller 12 that is spaced axially offset from the rollers 11 a and 11 b, with its axis 12 a (FIG. 1) parallel to and approximately midway between the axes 14 a and 14 b of the rollers 11 a and 11 b. This roller 12 is also height-adjustable so that the switch blade 3, when moved from its contacting position 5 to the spaced-apart position 6 and vice versa, is always supported by either the inner or outer roller 11 a or 11 b or the laterally offset roller 12 a. The rollers 11 a, 11 b, and 12 are here all of the same diameter which is such that their outer peripheries radially overlay each other, that is the inner portion of the roller 12 overlaps the outer portion of the roller 11 a and the outer portion of the roller 12 overlaps the inner portion of the roller 11 b. These diameters and the transverse spacing of the axes 14 a, 14 b, and 12 a are such that a spacing between the outer peripheries at a slide plane P of the support 9 is smaller than the transverse width of the bottom face of the rail foot 7. This assures that when the blade foot 7 is situated in the middle between two rollers 11 a and 12 as shown in FIG. 2 for the spaced-apart blade 3 (position 6), its edges continue to rest on and contact both rollers 11 a and 12.

Despite the lateral offset, the middle roller 12 bridges the gap between the rollers 11 a and 11 b, thus making it possible, even during the switch-throwing process as it rolls from the inner contacting position 5 into the outer position 6, for the narrow blade foot 7 to always rest on two rollers, i.e. roller 11 a and roller 12 or roller 11 b and roller 12. This assures a smooth, continuous rolling process of the switch blade 3, thus significantly reducing the blade-throwing force of the unillustrated actuator that shifts the blade 6 transversely.

As is clear from FIGS. 1 and 2, the rollers 11 a, 11 b, and 12 project upward and downward from the shared ribbed plate 13 of the slide frame 8 situated in the support 9. The entire subassembly formed by the frame 8 and rollers 11 a, 11 b, and 12 can travel transversely between the illustrated inner position close to the running rail 2 with the blade 3 resting against this running rail 2 to an unillustrated outer position. In the inner position the inner roller 11 a almost comes into contact with the s blade foot 7 and as a result, when the switch blade is being thrown, a rolling motion begins as early as possible, as soon as the blade 3 pulls away from the rail 2 and lifts slightly up off a support face or plane P of the support 9.

If an eccentric adjusting device 14 shown here only for the rollers 11 a and 11 b, but also supplied for the roller 12, sets the inner roller 11 a and the middle roller 12 lower than the outer roller 11 b, then the blade foot 7 can roll even more easily and in an almost infinitely variable fashion onto the inner roller 11 a and the laterally offset roller 12 and can also roll smoothly onto the outer roller 11 b. The height of the middle, laterally offset roller 12, however, should be preset so that it does not lie beneath the surface of the support 9. The devices 14 each have an eccentric core shaft 15 on which the respective roller 11 a, 11 b, or 12 is journaled and centered. 

1. In combination with a rail support forming an upwardly directed generally planar slide face; a longitudinally extending running rail secured to the support and having a foot with a predetermined transverse width; a longitudinally extending switch blade adjacent the rail and shiftable above the slide face between an inner position closely transversely juxtaposed with the running rail and an outer position transversely spaced from the running rail, a device comprising a frame defining a longitudinal outer axis spaced transversely along the slide face from the running rail, a longitudinal middle axis between the outer axis and the running rail, and an inner axis between the middle axis and the running rail; respective outer, middle, and inner rollers carried on the frame and rotatable about the respective axes, the middle roller being axially offset from the inner and outer rollers and being of such a diameter that it radially overlaps the inner and outer rollers.
 2. The device defined in claim 1 wherein the axes are transversely spaced and the rollers have outer peripheries of such diameter that a spacing between the outer periphery of the middle roller and the outer periphery of each of the inner and outer rollers on a plane of the slide face is less than the transverse width of the switch-blade foot.
 3. The device defined in claim 1, further comprising means for vertically shifting the middle axis and roller relative to the slide face.
 4. The device defined in claim 1 wherein the frame is a single plate supporting the inner, middle, and outer rollers.
 5. The device defined in claim 1 wherein the frame is shiftable transversely of the running rail.
 6. The device defined in claim 1 wherein the uppermost extent of the outer periphery of the inner roller is below the uppermost extent of the outer periphery of the outer roller.
 7. The device defined in claim 6 wherein the uppermost extent of the outer periphery is above that of the inner roller and above that of the outer roller.
 8. The device defined in claim 7 wherein the outer peripheries of the rollers define a plane on which the foot of the switch blade sits and that is inclined at a small acute angle downward toward the running rail.
 9. The device defined in claim 1 wherein the frame is also displaceable on the support between an innermost position juxtaposed closely with the running rail and an outermost position spaced well outward from the running rail, the foot of the switch blade being between the inner roller and the running rail and resting on the slide face in the innermost position of the frame. 